Laws, courts and authorities
TASL
Abbreviation for Title, Author, Source, License
In short and in plain language
TASL is a memory aid for giving credit for pictures under an open licence.
You name the title of the work, the author and the source. You also add a link to the licence.
This way you can usually credit images from others in the right way.
Definition
TASL is a rule of thumb for attributing images under a Creative Commons licence. It lists the title of the work, the author, the source and a link to the licence. This usually lets you credit third-party images on a website correctly.